ANI-Motionhttp://www.animot.com/This company designs and manufactures animated clothing. My personal favorite is the Harley-Davidson jacket, on which the back logo lights up when the bike's brakes are applied. [waugsqueke, Apr 15 2002]

Just to clarify: I'm thinking of something that comes on for a few seconds at a time. The overall exposure is determined by the user, but is portioned out over a few hours. This ensures the user isn't in the kitchen getting a midnight munchie and missing all the light. It also improves the odds of even exposure (since it's likely the user has moved since the last exposure)

I think there's a problem you may have overlooked, phoenix. As I understand it, optical fibers work precisely because they do not leak light through the fiber wall, but deliver the great majority of the light from one end of the fiber to the other. Fibers woven into a blanket are oriented so that the direction of light transfer required would be through the walls of the fiber, not the ends. To get light exposure from optical fibers in a blanket, the blanket would have to be constructed like a pile fabric (such as a velour, or a terry fabric). There are two problems with such a construction. One is that optical fibers are much larger than fibers typically used in such fabrics, so they would be quite abrasive and uncomfortable. The second is that the required construction is usually made by cutting loops of fibers, in order to expose the fiber ends. So pumping light into a set of fibers would allow all the light to exit where the fibers first enter a loop that has been cut, and all the other lengths of fiber that had been part of the original fibers before cutting, would remain dark.

Regarding the orientation of the optical fibers, there are now "side-emitting" fiber optics widely available that intentionally "leak" light out the sides so you can use them as accent lighting. I think these would do the trick.

One possible benefit of the "pile carpet" construction is that in addition to putting in light, you could also retrieve an image back out, in case you wanted to project what was going on under the covers onto the ceiling or such...